FIG. 1 is a configurative diagram of a general image forming device.
As shown in FIG. 1, the image forming device includes: a toner loading part 2 for loading a toner 1; a stirrer 3 mounted inside the toner loading part 2 for stirring the toner 1; a supply roller 4 mounted below the toner loading part 2 for transferring the stirred toner 1 to a development roller; the development roller 5 for developing the toner 1, which is transferred from the supply roller 4, into an electrostatic latent image formed on the surface of a photoconductive drum; a doctor blade 6 mounted on the development roller 5 for controlling the toner 1 formed on the surface of the development roller 5 to a uniform thickness; the photoconductive drum 7 mounted at one side of the development roller 5 and rotating at uniform peripheral speed; and a cleaning blade 8 being in contact with one side of the photoconductive drum 7.
Moreover, the image forming device further includes: a light exposure part 9 mounted at an upper end portion of one side of the photoconductive drum 7 for forming the electrostatic latent image on the surface of the photoconductive drum 7 charged electrically; an electric charge roller 10 mounted at an upper end portion of the other side of the photoconductive drum 7 for electrically charging a charge layer uniformly on the surface of the photoconductive drum 7; and a transfer roller 11 mounted at a lower end portion of the photoconductive drum 7 for transferring a toner image of the surface of the photoconductive drum 7 onto paper (P).
An operation of the image forming device will be described as follows.
First, the toner 1 loaded on the toner loading part 2 is stirred by the stirrer 3, moved toward the supply roller 4, and is supplied to the development roller 5 by a rotation of the supply roller 4.
Next, the surface of the photosensitive drum 7 is electrically uniformly charged by an electric action of the electric charge roller 10. Additionally, when the electrically charged part by the rotation of the photoconductive drum 7 receives an electric signal for forming an image through the light exposure part 9 and exposes the surface of the photoconductive drum 7, the light-exposed part forms an electrostatic latent image in an initially electrically charged state. In this instance, the electrostatic latent image of the photoconductive drum 7 is developed to the toner 1 and changed into a visible image while passing the development roller 5. Finally, the paper (P) mounted on a feeding cassette is fed by a feeding roller (not shown in the drawings), and then, the toner image of the surface of the photoconductive drum 7 is transferred to the paper (P) by a high pressure action of the transfer roller 11.
In the meantime, in the case of the image forming device, the quality of the image is dependent on how uniformly the thickness of the toner on the development roller is controlled to the doctor blade. Accordingly, because the doctor blade is rotated in contact with the development roller, the doctor blade is designed in consideration of durability, wear resistance, and others by a friction force, and there are many attempts to develop doctor blades having superior functions.
FIG. 2 is a perspective view of a doctor blade according to a prior art, and FIG. 3 is a sectional view showing a state where the doctor blade according to the prior art is mounted on a development roller.
As shown in the drawings, the doctor blade includes: a support member 20 for locating a blade adjacent to a development roller 5; an elastic layer 30 attached to the support member 20; and a shim 40 joined with the elastic layer 30, the shim in which a polyester layer 41 getting in contact with the development roller 5 and a conductive abrasive material layer 42 are laminated. Furthermore, the support member 20 and the elastic layer 30, and the elastic layer 30 and the shim 40 are adhered with each other by adhesive tapes 50 and 60.
However, the above-mentioned doctor blade has the following problems.
First, the shim 40 has a problem in that the quality of image is deteriorated because it is pushed forward and sprung forth by a rotary force of the development roller 5 as time goes by.
Second, because the adhesive tape 50 between the support member 20 and the elastic layer 30 and the adhesive tape 60 between the elastic layer 30 and the shim 40 may get softened or hardened due to a change in physical property and the thickness may be changed, it is difficult to uniformly control the thickness of the toner.
Third, the whole of the doctor blade assembly must be replaced with a new one when the abrasive material layer 42 of the shim 40 is abraded.